Just curious - what will happen if I point two instances of SolarWinds to the same DB

Terrible, terrible things. The only protection mechanisms that exists are when the Configuration Wizard is run and it detects that it's not the owner of the database. If you proceed, that Orion instance will take ownership and the other instance will be rendered broken.

Awesome, thanks Alterego, this just confirms my gut feeling that we should be super cautious here with our DR test runs

aLTeReGo​ quick question if I may:

If I will run the following script, which is part of app stack migration to new host, will it potentially stop original app host from messing up with the data should it come back to live?

DECLARE @oldHostname nvarchar(max)

SET @oldHostname = 'OLDHOST'

DECLARE @newHostname nvarchar(max)

SET @newHostname = 'NEWHOST'

UPDATE Engines SET ServerName = @newHostname WHERE ServerName = @oldHostname

UPDATE OrionServers SET HostName = @newHostname WHERE HostName = @oldHostname

UPDATE WebSettings SET SettingValue = @newHostname WHERE SettingName = 'JobSchedulerHost'

UPDATE Websites SET ServerName = @newHostname WHERE ServerName = @oldHostname

I see where you're going, but I don’t think that would be sufficient. After running that script, the new server will have replaced the old one (mostly – there are other references such as in the Subscriptions table). If the old server rises from the dead, it will see that it has no entry in the Engines table and it will create one. If it is an APE, this will have little or no effect. But if it is (was) a main server, it will register in the Engines table as a second main server and then things will be messed up.

Thanks alterego, this really clarifies a lot of things. Appreciate your help Thanks a million